905. What are the names of the subatomic and fundamental particles and what do they do? — BA, Fairbury, IL

Subatomic particles and fundamental particles aren't necessarily the same—some subatomic particles are built from several fundamental particles. That's the case for two of the most important subatomic particles: the proton and the neutron. Each of these particles is built from three fundamental particles known as quarks. The proton contains two "up" quarks and one "down" quark. The neutron contains one "up" quark and two "down" quarks. However, another important subatomic particle is also a fundamental particle: the electron. Virtually all matter is composed of these three subatomic particles: protons, neutrons, and electrons.

The list of fundamental particles—particles that are not known to be composed of other particles—is relatively short. It includes 6 types of quarks, which are given the arbitrary names "up", "down", "charm", "strange", "top", and "bottom". These quarks are never found by themselves but are instead used to build two major classes of subatomic particles: baryons (including protons and neutrons) and mesons. The list of fundamental particles also includes 6 types of leptons, which are given the names "electron", "electron neutrino", "muon", "muon neutrino", "tau", and "tau neutrino". These leptons are found by themselves and aren't used to build any other subatomic particles. These quarks and leptons are described as fermions and each has an associated antiparticle.

In addition to quarks and leptons, there are a number of fundamental particles that allow the fundamental fermions to interact with one another. These interaction particles are described as bosons and include the "photon", "W+ Boson", "W- Boson", "Z Boson", 8 different "gluons", and a particle called "Higgs" (which has not yet been observed but is thought to exist).

The list of subatomic particles that can be formed from the fundamental particles is extremely long and listing it here wouldn't be very enlightening. The only subatomic particles that are common in nature are protons, neutrons, electrons, and photons. Some of the others appear through nuclear or subnuclear processes in radioactive materials, nuclear reactors, particle accelerators, or celestial objects, but most of these exotic subatomic particles haven't been common since moments after the big bang.